This is the blog for Yale's undergrad course ANTH204:
An introduction to the patterns and processes of human genetic variation. Topics include: human origins and migration; molecular adaptations to environment, lifestyle and disease; ancient and forensic DNA analyses; and genealogical reconstructions.

Monday, October 8, 2012

New Evidence to Human Evolution

New DNA evidence has been discovered in the genomes of
modern hunter-gatherers of Africa. This evidence suggests that the development
of the human species was driven by ethnic groups interbreeding rather than a
superior original species

Members of the scientific community have long supported the
“Y Chromosome Adam” theory. This theory explains that human genetic sequencing
can be traced to one ancestor as the origin of the species. Genetically, Approximately
50,000 to 200,000 years ago, a doubling of the DAZ gene occurred in hominid
males creating larger amounts of testosterone. The higher levels of testosterone
led to the evolution of bigger and more developed brains

DNA evidence among modern hunter gathering tribes shows
foreign-looking stretches of DNA not common amongst its original ancestors. The
observations made of the Pygmies of Cameroon show that genetic differences in evolution
like smell, taste, immunity, and a genetic variant that explains the short
stature of the Pygmy people (4’11’’ avg. height). Similar foreign DNA could be
found in other tribes separated by geography like the Hadza and Sandawe who
have little to no intertribal contact.

Evidence suggests that “archaic” humans are the species
involved like Neanderthals and other protohuman species more closely related to
apes. They share ancient genetic material with “modern” species. The most
notable fossil with similar genetic ties found of a protohuman is the skull of
a “Homo Heidelbergensis”, a species existing 500,000 years ago and are
ancestors to Neanderthals.

It is unclear whether this “ancient” DNA from primitive
humans is helpful, harmful, or even relevant to humans today. The theory is
still relatively incomplete but opens up the possibility that humans originated
from different geographical positions. Also its important to note that Human
evolution developed differently for species in different regions. Genetic similarities
by no means guaranteed successful evolution as demonstrated by the point that
ancient unsophisticated protohumans could exist alongside far more complex
newly developing homo-sapiens.